Xerographic reproduction systems have become commonplace in the copy and print market, and such systems are now commonly found using laser polyson light modulators to control the image generation. Typically, such systems can be thought of as having two distinct sections, namely, the exposure section where the image is processed from a series of electrical signals into a modulated light image, and the reproduction section where the modulated image is presented to a light sensitive medium (the photoreceptor) whereupon the image is developed with a toner and subsequently transferred to a paper (or other) media in the standard manner. The transfer of toner to the photoreceptor is in response to the latent electrostatic image created by the modulated light image.
Any slight misadjustment of the optics of the exposure unit, or of the coordination of the exposure unit with the moving drum of the reproduction unit can degrade the printed output. Thus, the assembly of the exposure unit must be accomplished with precision and reproducibility.
This need for exacting alignments of the exposure unit, both internally, and with the mating reproduction unit, causes several problems in the manufacture of the system. These problems stem from the time and skill necessary to make all the necessary alignments as well as unit-to-unit consistency. Once made, it is important that the elements of the structure remain aligned in the field.
Accordingly, any attempt to make the exposure unit inexpensive must incorporate a simple assembly and alignment process that can be automated for repeatability. The latter assures that the normal skill levels of repair personnel are sufficient to effect field repair of the exposure unit.
Thus, a need exists in the art for a xerographic exposure unit manufacturing method and system which will allow both for economical initial assembly, and for straightforward replacement in the field. The system should be able to withstand movement, and should be easily realignable to the reproduction section if in fact it should become out of line during shipment or usage.